W6Mo5Cr4V2Al (M2Al), 501 Aluminum High Speed Steel- SCALE STEEL.

W6Mo5Cr4V2Al, referred to as 501, also known as M2Al, is on the basis of W6Mo5Cr4V2 carbon content from 0.08% ~ 0.90% to 1.05% ~ 1.15%, and add 1% Al and the formation of superhard high-speed steel, is a typical grade of aluminum high-speed steel.
High speed steel containing aluminum is an original [SCALE STEEL]steel in China, characterized by "no cobalt" and "low price".Because cobalt resources are scarce, replacing cobalt with aluminum is a feasible and favorable plan in China.Austrian BOHLER steel mill developed 501 similar steel class S620 based on the research of Chinese counterparts.

Chemical Composition(%) for W6Mo5Cr4V2Al (M2Al), 501 Aluminum High Speed Steel:
Standard GB/T 9943-2008(High Speed Tool Steel)
Grade W6Mo5Cr4V2Al W6Mo5Cr4V2
C 1.05~1.15 0.80~0.90
Si 0.20~0.60 0.20~0.45
Mn 0.15~0.40 0.15~0.40
P ≤0.030 ≤0.030
S ≤0.030 ≤0.030
Cr 3.80~4.40 3.80~4.40
V 1.75~2.20 1.75~2.20
W 5.50~6.75[SCALE STEEL] 5.50~6.75
Mo 4.50~5.50 4.50~5.50
Al 0.80~1.20 --

Heat Treatment（GB/T 9943-2008）for W6Mo5Cr4V2Al (M2Al), 501 Aluminum High Speed Steel:
Hardness under Annealed Treatment ≤269HBW
Preheating 800~900℃
Quenching Salt Bath Furnace 1200~1220℃
Box-Type Furnace 1230~1240℃
Quenching Medium Oil or Salt Bath
Tempering 550~570℃ for 1h[SCALE STEEL]
Tempering Times Twice
Hardness ≥65HRC

Example Case for Heat Treatment Process for W6Mo5Cr4V2Al (M2Al), 501 Aluminum High Speed Steel:
Preheating with Low Tem 450~500℃ for 1~1.5h
Preheating with Mid Tem 850~900℃，Heating Time According To The Effective Section 20~25s/mm
Heating by Quenching 1210±10℃，Heating Time According To The Effective Section 15~20s/mm
Cooling by Steps 580~620℃，Neutral Salt Bath[SCALE STEEL]
Air Cooling When The Furnace Is Cooled To 600℃, The Furnace Is Cooled To Room Temperature
Tempering with High Tem 550±10℃ for 2~3h
Tempering with MId Tem 530±10℃ for 2~3h
Three Times
Hardness 66~68HRC

Properties for W6Mo5Cr4V2Al (M2Al), 501 Aluminum High Speed Steel:
The hardness of 501 is 67~69HRC at room temperature and 54~55HRC at 600℃, making it more than W18Cr4V and comparable to superhard high-speed steel M42. The toughness and grinding performance are better than vanadium superhard high-speed [SCALE STEEL]steel.
Research shows that compared with W9Mo3Cr4V (W9) material, 501 price is the same, but 501 material tool processing efficiency increases 30%, cutting speed increases 58%, tool life extends 2~3 times.Compared with W2Mo9Cr4VCo8 (M42) material, the machining efficiency and cutting performance of 501 tool are basically the same, but the [SCALE STEEL]price of M42 is 3 times that of 501.
The defects of 501 are high vanadium content, poor grinding workability, strong overheating sensitivity, oxidation and decarbonization tendency, so protective measures should be taken during hot processing and heat treatment.

Applications for W6Mo5Cr4V2Al (M2Al), 501 Aluminum High Speed Steel:
The high speed steel 501 has the advantages of high hardness, wear resistance, high red hardness, high temperature hardness, good thermoplasticity and so on. It is made into cutting tools such as plane cutter, hob, broaching tool and so on.[SCALE STEEL] It has a good effect when it is used to process high-temperature alloy, ultra-high strength steel and other difficult cutting materials, and it is also used to make high load cold working die, such as cold extrusion die.